Supporting L3 femtocell mobility using the MOBIKE protocol

Proceeding of ACCESS 2011, The Second International Conference on Access Networks, Luxembourg City, Luxembourg, June 19-24, 2011Femtocells can be used to improve the indoor coverage and bandwidth of 3G cellular networks in homes and buildings. They are designed to be placed in a fixed location. However, their use would also be interesting in mobile environments such as public transportation systems. This paper studies the mobility limitations at the layer 3 and suggests an approach to support mobility on femtocell networks. This solution employs the protocols already defined in the femtocell architecture, minimizing thus the impact on it.This work has been supported by the Spanish Ministry of Science and Innovation, CONSEQUENCE project (TEC2010- 20572-C02-01) and partially supported by the Madrid regional community project CCG10-UC3M/TIC-4992

The New Grid

The New Grid seeks to provide mobile users with an additional method for off-grid communication, or communication without connection to Internet infrastructure. The motivation for this project was to find another alternative to Internet-dependent communication. Current Internet infrastructure is antiquated; it is expensive to maintain and expand, it has numerous vulnerabilities and high-impact points of failure, and can be rendered unusable for lengthy periods of time by natural disasters or other catastrophes. This current grid will eventually need to be replaced by a more modern, scalable, and adaptive infrastructure. The results of the projects research showed that implementing a library to allow for the creation of mobile peer-to-peer mesh networks could serve as a starting point for a transition from current Internet infrastructure to a more scalable, adaptive, and reliable Internet- independent network grid. Development of The New Grid largely followed the Rational Unified Process, in which the development process is split into four phases: requirements gathering, system design, implementation, and testing. Most of fall quarter was spent outlining functional requirements for the system, designing possible methods of implementation, and researching similar solutions that seek to transition mass mobile communication to a newer, more modern network grid. The New Grid differs from similar solutions because it has been implemented as a modular library. Current systems that allow for off-grid mobile connection exist as independent applications with a defined context and predetermined usability scope. We, the design team, found that implementing the system in the form of a modular library has multiple benefits. Primarily, this implementation would allow The New Grid to be deployed as widely as possible. Developers can both write applications around our library as well as include specific modules into existing applications without impacting other modules or introducing additional overhead into a system. Another benefit of deploying the system as a modular library is adaptability. The current, initial stable build of The New Grid uses Bluetooth Low Energy as its backbone for facilitating communication within large networks of mobile devices; however, this library could use any existing or future communication protocol to facilitate connection as long as a hook is written to allow The New Grid to interface with that protocol. Thus, The New Grid is not limited by which connection protocols currently exist, a property that other similar systems do not possess. The New Grid can be used in any application that requires connection between users. The most common applications would likely be messaging, file sharing, or social networking. While developers may find a variety of uses for The New Grid, its primary purpose is to facilitate reliable connection and secure data transfer in an environment with a large user base. Achieving this goal was proven feasible through research and testing the library with a small cluster of Android devices communicating solely with Bluetooth Low Energy. Expanding this group of a few phones to a larger mesh network of hundreds of devices was shown to be feasible through testing the librarys algorithms and protocols on a large network of virtual devices. As long as developers seek to create applications that allow users to communicate independent of Internet infrastructure, The New Grid will allow smartphone users to communicate off-grid and hopefully spur a switch from infrastructure-dependent mobile communication to user-centric, adaptive, and flexible connection

Génération optique de signaux millimétriques à base de modulateurs de phase optiques sans filtrage optique ou RF et sans polarisation électrique

National audienceUn système de génération optique d'ondes millimétriques accordable à base de modulateurs de phase sans filtre RF ni optique et sans tension de polarisation DC est proposé dans cet article. Un signal de 60 GHz est généré par multiplication par 8 à partir d'un signal de 7.5 GHz avec un ratio de suppression électrique en simulation d'environ 50 dB

Filterless millimetre-wave optical generation using optical phase modulators without DC bias

International audienceA tunable millimetre-wave generator using optical phase modulators with no DC bias and no filters (neither RF nor optical filters) is proposed in this paper. A 60 GHz RF signal is optically generated by multiplying the frequency of an input RF signal at 7.5 GHz by a factor of 8. The electrical suppression ratio is around 50 dB as shown by simulations

Congestion control Fast Recovery and Load Balancing in LAN

To control the congestion in local area network (LAN) Spanning tree protocol (STP) is used. Spanning Tree Protocol (STP) is IEEE approved standard 802.1 d. STP block the redundant ports in switched layer-2 networks. STP takes 30 to 60 seconds for recovering a link. Rapid spanning tree protocol (RSTP) is used to make the fast recovery for uplinks and downlinks. RSTP makes a fast recovery in switched network and takes seem less time to recover a link. Virtual local area networks (VLANs) and Multi instance spanning tree protocol (MSTP) is used to make load balancing and control the flood of BPDU’s in local area switched network. Virtual-Local Area Network (VLAN’s) and Multi Instance Spanning-Tree Protocol (MSTP) are associated with each other and Provide load balancing in switched network. Keywords: Spanning Tree Protocol (STP), Rapid Spanning Tree protocol (RSTP), Multi Instance Spanning Tree Protocol (MSTP), Virtual Local Area Network (VLAN), Bridge protocol data unit (BPDU), Switched Network

NaMANET – Nagy kiterjedésű mobil ad hoc hálózatok vizsgálata = NaMANET - Investigation of Large-Scale Mobile Ad Hoc Networks

A NaMANET projekt keretében elsősorban a nagy kiterjedésű mobil ad hoc hálózatok, valamint a vezeték nélküli közösségi hálózatok témájával foglalkoztunk. A mobil ad hoc hálózatok közvetlen adatátvitelt biztosító kommunikációs megoldásokra épülő lokális hálózatok, míg a vezeték nélküli közösségi hálózatok ideális körülményeket nyújthatnak ad hoc alkalmazások implementálására és bevezetésére mintegy összekötő gerinchálózatot biztosítva a mobil ad hoc hálózati szigetek számára. Kutatásaink során modelleztük és szimulációk segítségével vizsgáltuk az alkalmazásterjedést nagy kiterjedésű ad hoc hálózatokban. Összehasonlítottuk különböző szolgáltatásmenedzsment architektúrák teljesítőképességét. Megvizsgáltuk különböző információterjesztési stratégiák hatékonyságát járművek alkotta ad hoc hálózatokban, valamint megvizsgáltunk különböző klaszterezési eljárásokat biztonság és megbízhatóság szempontjából szenzor hálózatokban. Foglalkoztunk okostelefonok ad hoc hálózatokban való használatával. Terveztünk és implementáltunk egy szolgáltatástámogatási keretrendszert demo alkalmazásokkal, valamint megvizsgáltuk az ad hoc hálózatok alkalmazhatóságának kérdéskörét beltéri navigációs rendszer esetén. Foglalkoztunk vezeték nélküli közösségi hálózatok tervezési, kiépítési, üzemeltetési kérdéseivel, továbbá kidolgoztunk egy link állapotváltozást előrejelző eljárást vezeték nélküli hálózatokra. Eredményeinket számos nemzetközi konferenciacikk, folyóiratcikk és könyvfejezet formájában publikáltuk. | In the NaMANET project, we mainly focused on the investigation of large-scale mobile ad hoc networks, and the field of wireless community networks. In mobile ad hoc networks, the mobile nodes close to each other can communicate directly with their neighbors, since wireless community networks can provide ideal conditions as a backbone of the ad hoc network islands for implementing and deploying ad hoc applications. In our research, we modeled and via simulations investigated application spreading in large-scale ad hoc networks. We compared the performance of different service management architectures. We investigated the efficiency of different message spreading strategies in vehicular ad hoc networks, moreover surveyed and analysed clustering algorithms and protocols used in sensor networks from the viewpoint of security and reliability. We also dealt with using smartphones in ad hoc networks. We developed and implemented a service provisioning framework for ad hoc networks together with some demo applications, and investigated the usability of ad hoc networks in indoor navigation. Furthermore, we dealt with the area of developing, deploying and maintaining wireless community networks, and developed a link state prediction algorithm for wireless networks. We published our results in several international conference papers, journal papers and book chapters